Horn problem-there's always something.....

[Johnwindwood]

Guys

The Excel flew through the MOT today, despite me realising at the last minute that the horn wasn't working.
It played up once before-blowing a fuse when we were on holiday. Changed the fuse and back to normal.

This time, I checked the fuse, which had blown again. Put a new fuse in which promptly blew again instantly. (Ignition off.) The fuse only covers horn and cigar lighter.
So-any advice on what to check first. Is this likely to be a compressor or relay issue? (I realise that it could be wiring, but if I check the major components first.......)

Cheers

[Hawaiis0]

Cigar lighter...............
Disconnct the supply off the unit then fit a fuse

[Alan_M]

Cigar lighter...............
Disconnct the supply off the unit then fit a fuse

What he said - check nothing metallic has fallen into the cigarette lighter which will cause a short. Had this on another car.

[Johnwindwood]

Oh OK-I'll try it. Never had a cigar lighter fail on me before but theres always a first time!
Thanks.

[tonypoll]

If not the cigar lighter: the air pump for the horn is behind the driver's side headlamp pod (on the passenger's side for 1986 cars and after). When I fixed mine I removed the whole headlamp unit and then it was easy to get to the pump.
Whilst you are there, you may want to replace the plastic tubes from the pump to the horns, since these deteriorate with age, as was the case when I needed to fix mine. Attaching the tubing to the pump is easy. Fixing the tubes to the air horn is more difficult, unless you have a five year old with very small hands who is a willing volunteer.

[Johnwindwood]

Just feeding back on this-it was the fag lighter-the element was stuck in the socket and shorting to earth. Disconnected it and all fine now!

[Hawaiis0]

John - Just digging around for a spare fag lighter. Let you know when I find it.